$\dfrac{3}{5} - \dfrac{7}{12} = {?}$
Answer: $ = {\dfrac{3 \times 12}{5 \times 12}} - {\dfrac{7 \times 5}{12 \times 5}} $ $ = {\dfrac{36}{60}} - {\dfrac{35}{60}} $ $ = \dfrac{{36} - {35}}{60} $ $ = \dfrac{1}{60}$